There was a discussion on the Dual wastegate set up on the EVIL forum , what was said is , in order to use a single WG on two runners , there needed to be the "Y" piece to which the WG is attached , this "Y" piece is also connected to both runners so that exhaust gas from both rotors can be vented. But what actually happens when the gate is closed is a migration of pulses back and forth from rotor to rotor causing interference which results in (exhaust gas) power and velocity losses which could / would affect spool up negatively.

To have a truly divided system , there needs to separate gates to prevent the above phenomena from occurring.

 

Marcell thinks too much!



2 TiAL 35mm cost less and flow more than 1 TiAL 46mm though.

 

so if you have a 20b it would be smart to have 3 wastegates?

 

Si

 

No with a 20B you need not worry with all that for two reasons

1 . A 20 B has three exhaust ports and a devided turbo has two inlet ports , three cannot go into two without joining first , this is why most use non divided , single entry exhaust housings.

2 A 20B would have no trouble spooling a windmill because of the high volume of exhaust gas !! , there is no need to attempt to keep pulses separate and all that , all you would need is a large enough gate to handle the flow.

 

DuMaurier is correct as usual from what I've seen.

 

If you had 3 turbos, YES!

 

I think the big problem here is that people tend to get caught up in this bigger is better kinda thing and it isn't necessarily the right way to go, you would only need a very large wastegate if you are trying to maintain low levels of boost think of it this way the wastegates job is to modulate flow to the turbo, so if too much is going by the turbo it will have a harder time reaching higher levels, I think rather than so much emphasis being placed on the size of the wastegate, more should be placed on the flow through the wastegate.However with that being said there are many other variables that need to be taken into account.



-Sean